disease question?

[Diana]

I have a problem with a 6 line wrasse:

He has, so far only on the last third of its body(near the caudal and into the body), what seems like portruding scales covered by a whitish film......sorta like when a reptile sheds it's skin. It also seems to be slowly spreading.

He is still eating and active, the body looks sorta bloated around the infected area. I suspect something bacterial, possibly from an injury from introduction rituals from some blue damsels, but could be wrong...

Ideas? What to do for treatment.